Heat the oil in a large saucepan over medium heat. Add the onion with ¼ tsp salt and sauté until soft, about 5 minutes.
Add the sweet potato and cook until it begins to soften and brown, about 8 minutes.
Stir in coconut milk, tomato paste, curry powder, turmeric, ginger, and ½ tsp salt, plus 1 cup of water. Simmer over low heat until the mixture thickens, and potato is soft, about 10 minutes.
To make cauliflower rice: In a food processor, pulse the cauliflower in 2 batches until it is similar in size to rice grains.
Add cauliflower rice and chickpeas to the curry and cook for 5 minutes. Stir in the lime juice and season with more salt, if needed. Serve garnished with chopped cilantro.